Slide valve with multiple ports



ug. 8. i967 J. l.. MULLIN 3,334,896

SLIDE VALVE WITH MULTIPLE PORTS Filed Dec. 2, 1963 2 Sheets-Sheet lINVENTOR I JAMES L. MULUN BY 53 /Q 55 F103 ATTORNEY J. L. MULLIN SLIDEVALVE WITH MULTIPLE PORTS Aug. 8, i967 2 Sheets-Sheet 2 Filed Dec. 2,1963 INVENTOR vJAMES l. MULLIN BY ATTORNEY United States .Patent O3,334,896 SLIDE VALVE WITH MULTIPLE PORTS James L. Mullin, Wayne, Pa.,assignor to Burroughs Corporation, Detroit, Mich., a corporation ofMichigan Filed' Dec. 2, 1963, Ser. No. 327,326 13 Claims. (Cl. 271-74)This invention relates generally to valves, and more particularly tosliding-type valves for dispensing or applying fluid through multipleoutlets. While not limited thereto, the invention nds specialapplication as a control valve for sheet feeding mechanisms for holdingor releasing sheets of material at the top or end of a stack in a mannersomewhat similar to the control valve disclosed in U.S. Patent No.3,041,067, issued in the names of Aime Fux and Donald E. Kaplan,entitled Pneumatic Sheet Feeding Mechanism, and assigned to the sameassignee as the present invention.

An object of the invention is to provide an improved valve fordispensing or applying fluid through multiple outlets.

Another object of the invention is to provide a fastacting valve of thesliding type.

A further object of the invention is the provision of a high speed valvehaving particular utility for controlling the feeding of individualsheets of material from a stack of such items.

Another object of the invention is the provision of a high speed valvemechanism which alfords positive control of the duration of the timeinterval during which the valve mechanism is actuated.

Another object of the invention is to provide an electrically actuatedvalve having a shorter response time for a given length of actuatingsignal.

A further object of the invention is to provide a high speed valvemechanism whose response is consistent, cycle after cycle, and which isrelatively unalected in operation by its manufacturing tolerances.

Still a further object of the invention is the provision of an elongatedsliding valve member for opening and closing a plurality of oriliceshaving sealing faces arranged in a common plane, but without the needfor close tolerance on straightness of the Valve member.

-In accordance with the above objects, and first considered briey in its4broad aspects, the invention comprises a housing provided with a fluidchamber and associated ports each terminating in an enlarged orice orrecess in the fluid chamber. Each orifice has an area which exceeds thecross-sectional area of its associated port and the orifices are sopositioned that a slide valve member for opening and closing theorifices, and therefore their associated ports, need only be movedthrough la distancce less than the transverse dimension of each of theports to uncover each of the orifices to an extent in area substantiallyequal to the cross-sectional area of its associ- Y trol means for sheetfeeding, the housing is provided with an additional uid chamber and anadditional group of ports for applying fluid to obtain an initialholding force on the sheet material. In such case, other fluid releasedby movement of the slide valve will oppose this holding force to anextent enabling the controlled sheet to be fed away from the valvemechanism.

3,334,896 Patented Aug. 8, 1967 ice The invention will be more clearlyunderstood when the -following detailed description of a specificembodiment thereof is read in conjunction with the accompanying drawingsin which:

FIGURE 1 is an isometric view of a valve mechanism constructed inaccordance with the invention, and showing also, in phantom View, afragment of a flexible sheet or card to illustrate a particular utilityof the valve mechanism;

FIGURE 2 is a front elevational view of the mechanism of FIGURE 1 butwith certain parts omitted;

FIGURE 3 is a sectional view, on a reduced scale, taken along line 3-3of FIGURE 4;

FIGURE 4 is an enlarged sectional view taken along line 4-4 of FIGURE 2;

FIGURE 5 is an enlarged sectional view taken along line 5 5 of FIGURE 2;

FIGURE v6 is an enlarged sectional view of a fragment of the mechanismshown in FIGURE 4 taken along line 6 6 of that figure and illustratingthe slide valve in closed position;

FIGURE 7 is a view similar to FIGURE 6 but illustrating the slide valvein open position; and

FIGURE 8 is an enlarged sectional view of a fragment of the mechanismshown in FIGURE l taken along line 8 8 of that figure and showing aexible coupling for the slide valve and the means for attaching it to adriving member.

Turning now to the details of the drawings, and rst with reference toFIGURE 1 thereof, the preferred embodiment of the invention illustratedcomprises a Valve housing 10 in which is slidably mounted a slide valve12 for opening and closing a certain group of ports 14 associated withthe housing, a guide member 16 (FIGURES 4 and 5) for establishing orpositioning the slide valve 12 in close proximity to orices 18 of theports 14 (see also FIGURES 3, 6 and 7), and a driving means 20 (FIG- UREl) comprising a torque motor 22 and a flexible coupling 24 connectingthe slide valve 12 to the torque motor.

The valve housing 10 comprises a valve body 26 and an orifice plate 28.The valve body 26 is provided with an elongated rib 30 (FIGURES 4 and 5)in its interior establishing the position of two fluid chambers 32 and34, respectively, and a lateral foot or flange 36 (FIGURE 4) at itslower end. A conduit 38 connected to a source of fluid under pressure P(FIGURE 1) communicates with an L-shaped passage 40 (see also FIGURE 4)having a horizontal portion 40h and a vertical portion 40V opening atits upper end into the fluid chamber 32. A conduit 42 (FIGURE l)connected to a source of vacuum pressure V similarly communicates withthe fluid chamber 34 through an L-shaped passage 44 having a horizontalportion 44h and a vertical portion 44v opening at its upper end into theuid chamber 34. The flange 36 may be connected to a panel member 46(FIGURE 4) of associated apparatus in any suitable manner, as by screws48, yfor securing the valve housing to such apparatus.

The orifice plate 28 (FIGURE 3) includes a cover plate 50 and anelongated rib 52 which, together with the rib 30 of the valve body 26(FIGURE 5) form a wall which divides the valve housing 10 into the fluidchambers 32 and 34. At its lower end, the orifice plate 28 is secured tothe valve body 26 by screws 53 (FIGURE 4) which pass through the coverplate 50 and are screwed into the valve body 26, and at its upper regionit is secured to the valve body 26 by screws 54 which pass through therib 30 of the valve body and are screwed into the rib 52 of the orificeplate.

The external'surface 55 (FIGURES 2 and 5) of the ori-rice plate 28 isprovided with a series of shallow elongated grooves 56. Each one of agroup of ports 58 opens at one end into one of the grooves 56 and at itsother end into the iiuid chamber 34. Each one of the ports 14 similarlyopens at one end into one of the grooves 56, and at its other end intoan enlarged orifice or recess 18 in the fluid chamber 32. In the presentembodiment, each recess 18 is illustrated in one form as a substantiallyrectangular counterbore (FIGURES 3, 4 and 6) whose area, as viewed inFIGURE 6, exceeds the cross-sectional area of its associated port 14.Other shapes and forms of these orifices or recesses 18 may be used, aswill readily occur to those skilled in the art.

The inside face 60 (FIGURE 3) of the orifice plate 28, particularly theannular portions 60p (FIGURE 6) of this face 60 which surround theperiphery of the orifices 18, constitutes the sealing faces for theorifices, and it is against these surfaces 60p ythat the slide valve 12must be pressed to perform its sealing function. A series of pins 62(FIGURE 3), secured in the cover plate 50, extend into the uid chamber32 and provide a guiding means for positioning the slide valve 12laterally relative to the orifices 18, as may be seen most clearly inFIGURES 3 and 5.

The slide valve 12 (FIGURES 1, 4 and 5) is an elongated member, whichmay be generally at or rectangular in cross-section, as shown, and isprovided with a group of spaced-apart pads 64. The rightward face 66 ofeach pad 64, as viewed in FIGURES 1 and 4, constitutes, a sealing facefor covering one of the orifices 18 by sealing the peripheral sealingsurface 60p of the particular orifice 18, as indicated most clearly inFIGURE 6. The portions 68 (FIGURE 4)v connecting the pads 64 are madesufficiently thin so as to be flexible, thereby to enable the slidevalve 12 to flex and possibly ripple along its length, if necessary, toobtain a seal of all the orifices 18 in the closed position of the slidevalve. The slide valve 12 is positioned in close proximity to theorifices 18 by the guide member 16 so that when fluid under pressure isadmitted to the fluid chamber 32, as will be explained, the slide valve12 will make the initial seal most readily against the sealing surfaces60p. As shown in FIGURE 4, the slide valve 12 extends outward from theupper end of the valve housing through a rectangular bearing slot 70 inthe valve body 26.

The Vguide member 16 (FIGURES 4 and 5) is an elongated member, L-shapedin cross-section, and is provided with a long leg 72 secured to the ribS2, as by draw-in screws 74. The shorter leg 76 of the guide member 16establishes the slide valve 12 in close proximity to the sealingsurfaces 60p.

For reciprocably moving the slide valve 12, the drive means 20.(FIGURE 1) in this embodiment includes the torque motor 22 and theflexible coupling 24. The particular torque motor 22 illustrated is abistable torque motor especially designed by Servotronics, Inc., ofBuffalo, N.Y.

The torque motor- 22 is illustrated diagrammatically and, for purposesof this disclosure, comprises a body 77, fixed relative to the valvehousing 1t), and an armature 78 rockably mounted about the axis of thearmature pivot 80. By means of wire leads 82 the torque motor 22 iselectrically connected to an actuating device, not shown, for energizingthe motor to thereby rock the armature 78 on its pivot 80.

The armature 78 is connected to the slide valve 12 by means of theflexible coupling 24, which may be music wire, for example, andtherefore also elastic, and whose lower end 83 (FIGURE 8) is receivedinto a hole in the upper end of the slide valve 12 and rigidly securedthereto as by solder 84, or in any other suitable manner, and whoseupper end 86 extends into a spring collet 88 which is screwed into athreaded hole 90 in the armature 78. A collet clamping screw 92 isscrewed into the opposite end of the threaded hole 90 to thereby forcethe jaws 94 of the spring collet 88 together on the coupling wire end 86to secure it rigidly to the armature.

In the operation of the illustrated valve mechanism for controlling t-hefeeding of individual sheets of material from a stack of sheets which,for example, may be tabulating cards, fluid lunder vacuum pressure, inthis case air, is applied to the grooves 56 by the vacuum source Vthrough the conduit 42, the passage 44, the fluid chamber 34, and theports 58. Also, air under positive pressure is supplied to the fluidchamber 32 from the source P through the conduit 38 and passage 4i). Theslide valve 12 is initially in the closed position, as shown in FIG-URES 4 and 6, and the end card C of the stack, illustrated in phantomview in FIGURE l, is at this time wholly Iunder the control of thevacuum pressure being applied through the ports 58, and is thus held bysuction against the cardor sheet-engaging surface 35 of the orificeplate 28.

Whenever a card feed is called for, which may take place in thedirection indicated by the arrow 96, the torque motor 22 is energizedthereby rocking the armature 78 counterclockwise, as viewed in FIGURE 1,to a predetermined limit which in this embodiment is established by thebottom surface 97 of a slot 98 in the motor body 77. The slide valve 12will thereby be driven downwardly, and because of the transition fromangular motion of the armature 78 to linear motion of the slide valve12, the coupling 24 will ex laterally to some small extent, as willreadily be perceived.

The slide valve 12 will be driven downwardly a distance less than thetransversedimension of a port 14, taken in the direction of movement ofthe slide valve, and will thereby uncover a portion 100 (FIGURE 7) ofthe counterbores or orifices 18, each of which portion 100 is equal inarea to the cross-sectional area of the associated port 14, as vie-wedin FIGURE 7. Thus the orifices 18 are opened to an extent which enablesthem to fully supply the ports 14 with air.

Compressed air in the fluid chamber 32 will now flow through theorifices 18 into the ports 14, and thence into the grooves 56. Thecompressed air in the grooves 56 will diminish the card-holding force ofthe suction being applied through the ports 58 so that when the pressurein the space between the card C and the orifice plate 28 rises to acertain level, the vacuum pressure at the ports 58 will be ineffectivefor restraining feeding of the card, and the card will then be fed awayin the direction of the arrow 96 by a feeding device, not shown. At anappropriate time later, the torque motor 22 is again actuated to rockthe armature 78 clockwise, as viewed in FIGURE l, to restore the slidevalve 12 to closed position, at which time vacuum pressure appliedthrough the ports 58 will again be effective for holding the next cardto be controlled.

It will now be seen that the invention provides a fastacting valvemechanism wherein the slide valve `12 is moved through a shorter`distance than in prior art devices, and in which it is actuated by itsdriving means without any lost motion due to coupling connections.Furthermore, tolerance on straightness of the slide valve is notcritical since the flexible portions 68 connecting the pads 64 make theslide valve 12 flexibly yieldable to the force of fluid under pressurein the chamber 32, thereby to assure complete sealing of all theorifices 18 along the length of the slide valve.

While there has been shown a specific structure exemplary of theprinciples of the invention, it is to be understood that this is but oneembodiment thereof and that the invention may be constructed in avariety of sizes, shapes and modifications without departing from itstrue spirit and scope. Accordingly, it is to be understood that theinvention is not to be limited by the specific structure disclosed butonly by the subjoined claims.

What is claimed is:

1. A valve mechanism for controlling the feeding of sheet material froma stack comprising, a valve housing,

said housing comprising, a sheet engaging surface formed with shallowgrooves therein, a wall dividing the housing into first and second fluidchambers, a first group of ports each opening at one end into one ofsaid grooves and at its other end into said first fluid chamber, and asecond group of ports spaced apart and each opening at one end into oneof said grooves and terminating at its other end in an orifice in saidsecond fluid chamber, each said orifice being shaped substantially inthe form of a rectangular counterbore whose area exceeds thecross-sectional area of its associated port and each counterbore beingsurrounded by a peripheral sealing portion, a slide valve in said secondfluid chamber having a plurality of spaced apart substantiallyrectangular pads each provided with a face for contacting one of saidsealing portions and thereby sealing the associated orifice when theslide valve is in a first position, adjacent ones of said pads beingconnected by a flexible portion, a fixed guide member in Said secondfluid chamber positioning said slide valve in close proximity t-o saidsealing portions whereby fluid under pressure in said second fluidchamber will force the slide valve toward and therefore its pad facesinto contact with said sealing portions, a torque motor provided with apivotally mounted armature, and an elongated spring wire couplingrigidly -connected at its end portions, respectively, to said armatureand to said slide valve and flexible in a transverse direction, andwherein rocking movement of said armature on its pivotal mounting willmove said slide valve to a second position through a distance less thanthe transverse dimension `of each port of said second group of portstaken in the direction of movement of said slide valve to uncover eachof said orifice counterbores to an extent in area substantially equal tothe cross-sectional area Iof its associated port.

2. A valve mechanism for controlling the movement of sheet materialcomprising, a valve housing, said housing comprising, a sheet engagingsurfacee formed with shallow grooves therein, first and second fluidchambers, a first group of ports' each opening at one end into one ofsaid grooves and at its other end into said first fluid charnber, and asecond group of ports spaced apart and each opening at one end into oneof said grooves and terminating at its other end in an orifice in saidsecond fluid chamber, each said orifice being shaped substantially inthe form of a counterbore whose area exceeds the crosssectional area ofits associated port and each counterbore being surrounded by aperipheral sealing portion, a slide valve in said second fluid chamberhaving a plurality of spaced apart pads each provided with a face forcontacting one of said sealing portions and thereby sealing theassociated orifice when the slide valve is in a first position, adjacentones of said pads being connected by a flexible portion, a guide memberin said second fluid chamber positioning said slide valve in closeproximity to said sealing portions whereby fluid under pressure in saidsecond fluid chamber will force the slide valve toward and therefore itspad faces into contact with said sealing portions, a torque motorprovided with a pivotally mounted armature, and an elongated springcoupling rigidly connected at its end portions, respectively, to saidarmature and to said slide valve and bendable elastically in atransverse direction, and wherein rocking movement of said armature onits pivotal mounting will move said slide valve to a second positionthrough a distance less than the transverse dimension of each port ofsaid second group of ports taken in the direction of movement of saidslide valve to uncover each of said orifice counterbores to an extent inarea substantially equal to the crosssectional area of its associatedport.

3. A valve mechanism for controlling the movement of sheet materialcomprising, a valve housing, said housing comprising, a sheet engagingsurface formed with shallow grooves therein, a wall dividing the housinginto first and second fluid chambers, a first group of ports eachopening at one end into one of said grooves and at its other end intosaid first fluid chamber, and a second group of ports spaced apart andeach opening at one end into one of said grooves and terminating at itsother end in an orifice in said second fluid chamber, each said orificebeing shaped in the form of a recess whose area exceeds thecross-sectional area of its associated port and each recess beingsurrounded by a peripheral sealing porftion, a slide valve having aplurality of spaced apart pads each provided with a face for contactingone of said sealing portions and thereby sealing the associated orificewhen the slide valve is in a first position, adjacent ones of said padsbeing connected by a flexible portion, a torque motor provided with apivotally mounted armatture, and an elongated coupling rigidly connectedat its end portions, respectively, to said armature and to said slidevalve and flexible in a transverse direction, and wherein rockingmovement of said armature on its pivotal mounting will move said slidevalve to a second position through a distance less than the transversedimension of each port of said second group of ports taken in thedirection of movement of said slide valve to uncover each of saidorifices to an extent in area substantially equal to the cross-sectionalarea of its associated port.

4. A valve mechanism for controlling the movement of sheet materialcomprising, a valve housing, said housing comprising, a sheet engagingsurface formed with grooves therein, first and second fluid chambers, afirst group of ports each opening at one end into one of said groovesand at its other end into said first fluid chamber, and a second groupof ports spaced apart and each opening at one end into one of saidgrooves and terminating at its other end in an orifice in said secondfluid chamber, each said orifice being shaped in the form of a recessWhose area exceeds the cross-sectional area of its associated port andeach recess having a sealing portion at its periphery, a slide valvehaving a plurality of spaced apart pads each provided with a face forcontacting one of said sealing portions and thereby sealing theassoicated orifice when the slide valve is in a first position, adjacentones of said pads being connected by a flexible portion, a drive meansprovided with a rockable armature, and an elongated coupling rigidlyconnected at its end portions, respectively, to said armature and tosaid slide valve and flexible in a transverse direction, and whereinrocking movement of said armature will move said slide valve to a secondposition through a distance less than the transverse dimension of eachport of said second group of ports taken in the direction of movement ofsaid slide valve to uncover each of said orifices to an extent in areasubstantially equal to the cross-sectional area of its associated port.

5. A valve mechanism comprising, a housing provided with an internalfluid chamber and a group of ports each opening at one end into anoutside face of said housing and terminating at its other end in anorifice in said fluid chamber, each said orifice being shapedsubstantially in the form of a counterbore whose area exceeds thecrosssectional area of its associated port and each counterbore beingsurrounded by a peripheral sealing portion, a slide valve in said fluidchamber having a plurality of spaced apart pads each provided with aface for contacting one of said sealing portions and thereby sealing theassociated orifice when the slide valve is in a rst position, adjacentones of said pads being connected by a flexible portion, a guide memberin said fluid chamber for positioning said slide valve in closeproximity to said sealing portions whereby fluid under pressure in saidfluid chamber will force the slide valve toward and therefore its padfaces into contact with said sealing portions, a torque motor providedwith a pivotally mounted armature, and an elongated coupling rigidlyconnected at its end portions, respectively, to said armature and tosaid slide valve and being flexible in a transverse direction, andwherein rocking movement of said armature on its pivotal mounting willmove said slide valve to a second position through a 7 distance lessthan the transverse dimension of each of said ports taken in thedirection of movement of said slide valve to uncover each of saidorifice counterbores to an extent in area substantially equal to thecross-sectional area of its associated port.

6. A valve mechanism comprising, a housing7 provided with a Huid chamberand a group of ports each opening at one end into the outside of saidhousing and terminating at its other end in an orifice in said fiuidchamber, each said orifice being shaped substantially in the form of acounterbore whose area exceeds the cross-sectional area of itsassociated port and each counterbore being surrounded by a peripheralsealing portion, a slide valve having a plurality of spaced apart padseach provided with a face for contacting one of said sealing portionsand thereby sealing the associated orifice when the slide valve is in afirst position, adjacent ones of said pads being connected by a flexibleportion, guide means positioning said slide valve in close proximity tosaid sealing portions whereby fluid under pressure in said fluid chamberwill force the slide valve toward and therefore its pad faces intocontact with said sealing portions, a motor provided with a rockablearmature, and an elongated coupling rigidly connected at its endportions, respectively, to said armature and to said slide valve andbeing liexible in a transverse direction, and wherein rocking movementof said armature will move said slide valve to a second position througha distance less than the transverse dimension of each of said portstaken in the direction of movement of said slide valve to uncover eachof said orifice counterbores to an extent in area substantially equal tothe crosssectional area of its associated port.

7. A valve mechanism comprising, a housing provided with an internalfluid chamber and a group of ports each opening at one end into anoutside face of said housing and terminating at its other end in anorifice in said uid chamber, each said orifice being shapedsubstantially in the form of a rectangular recess whose area exceeds thecross-sectional area of its associated port and each recess beingsurrounded by a peripheral sealing portion, a slide valve in said uidchamber having a plurality of spaced apart pads each provided with aface for contacting one of said sealing portions and thereby sealing theassociated orifice when the slide valve is in a first position, saidslide valve being flexibly yieldable to the force of fiuid underpressure to effectuate said sealing, a motor provided with a pivotallymounted armature, and an elongated fiexible coupling rigidly connectedat its end portions, respectively, to said armature and to said slidevalve, and wherein rocking movement of said armature on its pivotalmounting will move said slide valve to a second position through adistance less than the transverse dimension of each of said ports takenin the direction of movement of said slide valve to uncover each of saidorifices to an extent in area substantially equal to the cross-sectionalarea of its associated port.

8. A valve mechanism comprising, a housing provided with an internalfluid chamber and a group of ports each opening at one end into anoutside vface of said housing and terminating at its other end in anorifice in said fluid chamber, each said orifice 'being shaped in theform of a recess whose area exceeds the cross-sectional area of itsassociated port and each recess being surrounded by a peripheral sealingportion, a slide valve in said fluid chamber having a plurality ofspaced apart pads eac-h provided with a face for contacting one of saidsealing portions and thereby sealing the associated orifice when theslide valve is in a first position, said slide valve being flexiblyyieldable to the force of lfiuid under pressure to effectuate saidsealing, a motor provided with a rockable armature, and an elongatedfiexible coupling rigidly connected at its end portions, respectively,to said armature and to said slide valve, and wherein rocking movementof said armature will move said slide valve to a second position througha distance less than the transverse dimension of each of said portstaken in the direction of movement of said slide valve to uncover eachof said orifices to an extent in area substantially equal to thecross-sectional area of its associated port.

9. A valve mechanism comprising, a housing provided with an internalfiuid chamber and a group of ports each opening at one end into anoutside surface of said housing and terminating at its other end in anorifice in said fluid chamber, each said orifice being shaped in theform of a recess whose area exceeds the cross-sectional area of itsassociated port and each recess being surrounded by a peripheral sealingportion, a slide valve in said fluid chamber having a plurality ofspaced apart pads each provided with a face for contacting one of saidsealing portions and thereby sealing t-he associated orifice when theslide valve is in a first position, said slide valve being fiexiblyyieldable to the force of fiuid under pressure to effectuate saidsealing, an angularly movable drive member, and an elongated laterallyflexible coupling rigidly connected at its end portions, respectively,to said drive member and to said slide valve, and W-herein angularmovement of said drive member will move said slide valve linearly to asecond position through a distance less than the transverse dimension ofeach of said ports taken in the direction of movement of said slidevalve to uncover each of said orifices to an extent in areasubstantially equal to the cross-sectional area of its associated port.

10. A valve mechanism comprising, a housing provided With a fluidchamber and a group of ports each opening at one end into an outsidesurface of said lhousing and terminating at its other end in an enlargedorifice in said iiuid chamber, each said orifice having an area whichexceeds the cross-sectional area of its associated port and having asealing portion at its periphery, a slide valve having a plurality ofspaced` apart pads each provided with a face for contacting one of saidsealing portions and thereby sealing the associated orifice when theslide valve is in a first position, said slide valve being flexiblyyieldable to the force of fluid under pressure to effectuate saidsealing, an angularly movable drive member, and an elongated fiexiblecoupling rigidly connected at its end portions, respectively, to saiddrive member and to said slide valve, and wherein angular movement ofsaid drive member will move said slide valve linearly to a secondposition through a distance less than the transverse dimension of eachof said ports taken in the direction of movement of said slide valve touncover each of said orifices to an extent in area substantially equalto the cross-sectional area of. its associated port.

11. A valve mechanism comprising, a housing provided with a iiuidchamber and a group of ports each opening at one end into an outsidesurface of said housing and terminating at its other end in an enlargedorifice in the form of a recess in said fluid chamber, each said orificehaving an area which exceeds the cross-sectional area of its associatedport and having a sealing portion at its periphery, a slide valve havinga plurality of sealing faces each for contacting one of said sealingportions and thereby sealing the associated orifice when the slide valveis in a first position, said slide valve being flexibly yieldable to theforce of fluid under pressure to effectuate said sealing, and means formoving said slide valve to a second position through a distance lessthan the transverse idimension of each of said ports taken in thedirection of movement of said slide valve to uncover each of saidorifices to an extent in area substantially equal to the cross-sectionalarea of its associated port.

12. A valve mechanism comprising, a housing provided with a fiuidchamber and a lgroup of ports each opening at one end into an outsidesurfaec of said housing and terminating at its other end in an enlargedorifice in the -form of a recess in said uid chamber, each saidoricehaving an area. which exceeds the cross-sectional area of itsassociated port and having a sealing portion at its periphery, a slidevalve having a plurality of sealing faces each for contacting one ofsaid sealing portions and thereby sealing the associated orice when theslide valve is in a rst position, and means for moving said slide valveto a second position through a distance less than the transversedimension of each of said ports taken in the direction of 'movement ofsaid slide valve to uncover each of said orifices to an extent in areasubstantially equal to the cross-sectional area of its associated port.

13. A valve mechanism comprising, a housing provided With a iuid chamberand a-port opening at one end into an outside surface of said housingand terminating at its other end in an enlarged oriiice in the form of arecess in said fluid chamber, said orifice having an area which exceedsthe cross-sectional area of said port and having a sealing portion atits periphery, a slide valve having a sealing face -for contacting saidsealing portion and thereby sealing said orifice when the slide valve isin a rst position, and means for moving said slide valve to a secondposition through a distance less than the transverse dimension of saidport taken in the direction of movement of said sli-de valve to uncoversaid orice to an extent in area substantially equal to thecross-sectional area of said port.

References Cited UNITED STATES PATENTS 6/1884 Johnson 137-625.33

8/1925 Jung 251-205 X

13. A VALVE MECHANISM COMPRISING, A HOUSING PROVIDED WITH A FLUIDCHAMBER AND A PORT OPENING AT ONE END INTO AN OUTSIDE SURFACE OF SAIDHOUSING AND TERMINATING AT ITS OTHER END IN AN ENLARGED ORIFICE IN THEFORM OF A RECESS IN SAID FLUID CHAMBER, SAID ORIFICE HAVING AN AREAWHICH EXCEEDS THE CROSS-SECTIONAL AREA OF SAID PORT AND HAVING A SEALINGPORTION AT ITS PERIPHER, A SLIDE VALVE HAVING A SEALING FACE FORCONTACTING SAID SEALING PORTION AND THEREBY SEALING SAID ORIFICE WHENTHE SLIDE VALVE IS IN A FIRST POSITION, AND MEANS FOR MOVING SAID SLIDEVALVE TO A SECOND POSITION THROUGH A DISTANCE LESS THAN THE TRANSVERSEDIMENSION OF SAID PORT TAKEN IN THE DIRECTION OF MOVEMENT OF SAID SLIDEVALVE TO UNCOVER SAID ORIFICE TO AN EXTENT IN AREA SUBSTANTIALLY EQUALTO THE CROSS-SECTIONAL AREA OF SAID PORT.